Pyrotechnic circuit breakers are widely used for disabling an electric circuit, for instance in response to abnormal conditions of use.
Conventional pyrotechnic circuit breakers use a bus bar acting as a conducting element, which can be cut or broken along its transverse direction into two distinct parts by a piston in order to break open the circuit by stopping the electric conduction between the two parts of the bus bar. In the present text, we will refer to the cutting of the bus bar by the piston, to designate either its cutting or its breaking by the piston.
Document EP 2660842 discloses a known circuit breaker which comprises a cutting tool with two distinct cutting edges, configured to be at different heights from the bus bar.
In such pyrotechnic circuit breakers, a recurring issue resides in the reliability of the cut of the bus bar, while ensuring a proper electrical conduction when the circuit is in operation.
The bus bar indeed needs having a thickness sufficient for providing appropriate electric conduction properties. However increasing the thickness of the bus bar makes its cutting more difficult, and therefore requires an oversizing of the piston for ensuring a reliable cut, which results in an oversizing of the whole device.